If you want to build a better TCP, do it. But hacking one in on top of UDP was a cheat that didn’t pay off. Well, assuming performance was even the actual goal.
I don't know how familiar the developers of QUIC were with SCTP in particular but they were definitely aware of the problems that prevented a better TCP from existing. The only practical solution is to build something on top of UDP, but if even that option proves unworkable, then the only other possibility left is to fragment the Internet.
If you've followed Dave Taht's bufferbloat stuff, the reason he lost faith in TCP is because middle devices have access to the TCP header and can interfere with it.
If SCTP got popular, then middle devices would ruin SCTP in the same way.
QUIC is the bufferbloat preferred solution because the header is encrypted. It's not possible for a middle device to interfere with QUIC. Endpoints, and only endpoints, control their own traffic.